<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width,initial-scale=1,minimum-scale=1,maximum-scale=1,user-scalable=no" />
        <title></title>
        <style type="text/css">
            *{
                margin: 0;
                padding: 0;
            }
            html,body{
                height: 100%;
            }
            #wrap{
                min-height: 100%;
            }
            #footer{
                height: 50px;
                background: pink;
                line-height: 50px;
                text-align: center;
                margin-top: -150px;
            }
            #main{
                text-align: center;
                padding-bottom: 150px;
            }
        </style>
    </head>
    <body>
        <div id="wrap">
            <div id="main">
                n <br/>
                n <br/>
				n <br/>
            </div>
        </div>
        <div id="footer">footer</div>
    </body>
	<script>
		const target = { a: 1, b: 2 }; 
		const source = { b: 4, c: 5 };
		const a = Object.assign(target,source)
		console.log('a',a);
	</script>
</html>